Rotor system and method for manipulating liquid matter

ABSTRACT

A rotor system including a rotor having a plurality of cavities disposed radially and in concentric array about the rotational axis of the rotor for receiving and retaining respective quantities of liquid, each cavity having an overflow through which liquid in excess of the volumetric capacity of the cavity is expelled upon rotation of the rotor, and displacement means of known displacement volume movable into each cavity upon rotation of the rotor whereby a known quantity of liquid is displaced from each cavity and expelled from the rotor into appropriate receptacles. The method disclosed includes the step of admitting gross quantities of liquid to the rotor cavities initially and expelling the liquid in excess of the cavity volume by rotating the rotor. Subsequently, in accordance with the disclosed method, the rotor is rotated with a displacement body in each cavity to expel a further, but known, quantity of liquid from each cavity.

United States Patent Hatcher, Sr.

[541 ROTOR SYSTEM AND METHOD FOR MANIPULATING LIQUID MA'I'I'ER Inventor:Donald W. Hatcher, Sr., Route 4,

Box 207, Clinton, Tenn. 37716 Filed: 0a. 13, 1970 Appl. No.2 80,347

[51] Int. Cl ..B65b l/04, B65b 3/04 [58] Field of Search ..l41/1, 34,l15-127, 141/283, 129

References Cited UNITED STATES PATENTS 3/1965 Unger ..l4l/34 PrimaryEraminer-l-louston S. Bell, Jr. AttorneyAnderson, Luedeka, Fitch, Even &Tabin U.S.Cl. ..l4l/l, 141/34, 141/115,

[15] 3,683,973 [4 1 Aug. 15, 1972 [5 7] ABSTRACT A rotor systemincluding a rotor having a plurality of cavities disposed radially andin concentric array about the rotational axis of the rotor for receivingand retaining respective quantities of liquid, each cavity having anoverflow through which liquid in excess of the volumetric capacity ofthe cavity is expelled upon rotation of the rotor, and displacementmeans of known displacement volume movable into each cavity uponrotation of the rotor whereby a. known quantity of liquid is displacedfrom each cavity and expelled from the rotor into appropriatereceptacles. The method disclosed includes thestep of admitting grossquantities of liquid to the rotor cavities initially and expelling theliquid in excess of the cavity volume by rotating the rotor,Subsequently, in accordance with the disclosed method, the rotor isrotated with a dis placement body in each cavity to expel a further, but

known, quantity of liquid from each cavity.

8 Claims, 9 Drawing, Figures Moan-0'12 Patented Aug. 15, 1972 3Sheets-Sheet 2 MW Mm 5M 12110;

Patented Aug. 15, 1972 3,683,973

3 Sheets-Sheet 5 6). FIGE) A7 a noun-o2 A2) I I PIC-3.6

LAMP

INVENTOQ T TYE).

ROTOR SYSTEM AND METHOD FOR MANIPULATING LIQUID MATTER This inventionrelates to rotor systems and particu larly to methods and apparatus formanipulating liquids employing a rotor system.

There exist several commercially available centrifuge systems which areprimarily useful for rapidly and accurately carrying out variousanalytical procedures, including medical diagnostic procedures.Generally, as carried out in a centrifugation system, these proceduresinvolve the introduction of two or more measured quantities of liquid (aspecimen plus one or more reagents) into receptacles, termed cuvettes,where a chemical reaction takes place. In the usual centrifugationsystem, a plurality of cuvettes, l6 for example, are positioned aroundthe periphery of a central rotor having a corresponding number ofcavities. A first quantity of a sample, human blood for example, ismeasured into each of a first set of separate cavities of the rotor. Asecond set of cavities in the rotor are provided with a reagent, forexample. The blood and reagent are spun from the two sets of cavities(l6 cavities per set) in the rotor into the 16 corresponding cuvettessimultaneously. Identical reactions occur in the 16 revolving cuvettes.The progress of the reactions in the several cuvettes may be observed byknown means, such as by monitoring the transmission of a light beampassing through the cuvettes (which are transparent themselves) as theyare rotated through the beam.

Heretofore it has been common practice to introduce a measured quantityof sample or reagent into each of the individual cavities in the rotorby pipetting or like technique. In addition to the known inaccuracy ofpipetting operations, their time consuming nature has limited theusefulness of centrifugation in diagnostic procedures and other analysesby so increasing the time required to complete a full procedure that theadvantages of centrifugation are lost or overshadowed by the timeelement.

It is an object of the invention disclosed herein to provide an improvedrotor system. It is also an object to provide a method and apparatus formanipulating a liquid employing a rotor system. It is also an object toprovide an inexpensive rotor system whose components are designed to beof the single-use type.

Other objects and advantages of the invention will be recognized fromthe following description, including the drawings. In the drawings:

FIG. 1 is a representation of apparatus for observing the status ofliquids in a centrifuge and depicting various features of the presentinvention;

FIGS. 2, 2A and 2B are a representation of a rotor constructed inaccordance with the present invention and including various constructiondetails of the rotor and a collector ring within which the rotor isfitted;

FIG. 3 is a cross-sectional view of the rotor of FIG. 2 taken along theline 3-3 of FIG. 2;

FIG. 4 is a plan view of a rotor system depicting various features ofthe present invention;

FIG. 5 is a cross-sectional view of a rotor system including means fordispensing displacement bodies into several cavities of the rotor;

FIG. 6 is a representation of a rotor system including a plurality ofrotors and also including means for dispensing displacement bodies intothe several cavities of one of the rotors by means of centrifugalforces; and

FIG. 7 is a cross-sectional view of the displacement body dispensingmeans shown in FIG. 6 and taken along the line 7 7 of FIG. 6.

In accordance with the method disclosed herein, a preselected quantityof liquid matter, sample or reagent for example, is admitted to one ormore central holding chambers in a centrifuge rotor. Each chamber isprovided with a radially outward cavity portion which is in fluidcommunication with the respective central chambers. Each cavity isprovided with an overflow including a weir and is adapted to receive andretain a quantity of liquid matter when the rotor is rotated at a speedsuch as displaces the liquid radially outward. After loading of theliquid into the holding chambers, the rotor is rotated whereupon theliquid movesoutwardly from the chambers proper into the severalcavities. Further, any liquid in excess of the capacity of therespective radially outward cavities at the instant rotational speed ofthe rotor is caused to overflow the respective weirs and be expelledthrough the overflows. Thereupon the rotor is brought to its restposition and appropriate cuvettes are positioned adjacent the respectiveoverflows of the cavities. To each of the radially outward cavitiesthere is introduced a body having a displacement volume substantiallyequal to the volume of the preselected quantity of liquid which it isdesired to dispense into each of the cuvettes. Upon subsequent rotationof the rotor whose respective cavities are each loaded with liquid and adisplacement body, and with the cuvettes in position at the respectiveoverflows of the cavities, the displaced quantities of liquid overflowthe respective weirs, are expelled through the overflows and collectedin the respective cuvettes. Several diverse liquids may be dispensedinto the cuvettes successively or simultaneously as will appear morefully hereinafter.

Apparatus for carrying out the disclosed method is described herein andpreferably includes a demountable rotor for purposes which will appearhereinafter. Apparatus for introduction of the several displacementbodies into the respective cavities of the rotor also will be described.

To facilitate an understanding of the method of the disclosed invention,apparatus for carrying out the method will be discussed. The basiccentrifugation system employed in the disclosed method is depicteddiagrammatically in FIG. l and need only be referred to in general termssince suitable systems are available from commercial sources andwell-known in the art. Generally this system comprises a centrifuge 5including a housing 6, normally circular in geometry, rotatably mountedby suitable means (not shown) and providing support for a central rotor7 and a plurality of cuvettes 8 disposed in the peripheral region of thehousing. Both the rotor and cuvettes usually are rotatable with thehousing. The cuvettes usually comprise openings cut in the inner wall ofa transparent ring 9, this ring being mounted in the housing and held inplace by an annular clamp 10. A light beam 11 from a lamp 12 may bedirected through the cuvettes as they spin through the beam. Thetransmission of the beam through a cuvette (when a sample is in thecuvette) may be monitored and/or recorded as a measure of the state orquality of the matter contained in the cuvette.

Referring to FIG. 2, the present invention includes a rotor 7,preferably of circular configuration. The periphery of the rotor may beprovided with toothed portions 14 adapted to engage respective slotportions of an annular collector ring 9 thereby providing a connectionbetween the rotor and ring 9. This ring 9 preferably is rotatably heldwithin a housing 6 (see FIG. 1) thereby providing rotatable mounting ofthe rotor within the centrifugation system.

The rotor 7 preferably is divided centrally into a plurality of chambers13 of generally equal volumes. Each of these chambers 13 preferablydiverges radially outward to contact a curved, but generally vertical,wall 16 thus defining a cavity 17 at the most radially outward portionof each chamber 13. The several chambers 13 are separated by partitions18 which define the lateral extremities of the chamber 13 and thecavities 17. Each cavity 17 is provided with an overflow 20 whoseradially inward opening defines a weir 21 over which liquid matter willflow upon rotation of the rotor as will be discussed hereinafter.Preferably each chamber is partly covered in the region of itsrespective cavity portion by a top wall portion 19 which slopesdownwardly toward cavity 17 so that upon rotation of the rotor anyliquid droplets or the like present on the top wall portion will beforced into the cavity 17 or caused to exit the chamber through overflow20 under the influence of the centrifugal forces developed by therotating rotor. It is noted that in a preferred embodiment, the radiallyoutward termination of each overflow 20 is disposed on one of thetoothed projections 14 on the periphery of the rotor. As shown in FIG.2, when the toothed projection 14 of the rotor is disposed within itscorresponding indention 15 in the collector ring 9, the terminus of theoverflow 20 is disposed centrally of a cuvette 8 in the collector ringand there is no opportunity for misalignment between an overflow and itscorresponding cuvette.

Preferably the rotor 7 may be provided with a central hollow post 22 forreceiving a displacement body dispersing unit as will appear more fullyhereinafter.

Alternatively, the several partitions 18 defining the chambers 13 mayconverge to a central axis without including a central post.

FIG. 3 depicts the rotor 7 in cross section, the view of I the liquid inthe chamber, liquid in excess of the volumetric capacity of the cavitywill overflow weir 21 and be expelled from the chamber through overflow20. During such rotation of the rotor, any liquid splattered on the topwall 19 in the form of droplets or the likewill be forced radiallyoutward and either expelled through the overflow 21 or moved into thecavity. Consequently, under the centrifugal forces developed at a givenrotational speed of the rotor, the several cavities of the rotor can becaused to contain identical quantities of liquid, assuming each chamber13 was provided initially with a quantity of liquid at least equal to orin excess of the volumetric capacity of each cavity and the severalcavities are of identical volumetric capacity. It is not required,however, that the several cavities be of identical volumetric capacityfor as will be discussed, it is the displaced liquid which is of ameasured volume. In any event, because of its respective geometricconfiguration, each of the cavities will retain a selected volume ofliquid regardless of the rotational speed of the rotor so long as suchrotational speed is at least equal to or in excess of the rotationalspeed which will cause the liquid in the respective chambers to be.displaced into the cavities and held against the curved wall 16 of eachcavity. Preferably the rotor is rotated sufficiently fast to cause theradially inward surface of the liquid in each of the cavities to definea substantially vertical wall such as shown by the dotted line 23 ofFIG. 2A.

FIG. 4, a generally plan view taken along the line 4- 4 of FIG. 1,depicts the rotor 7 disposed within its encompassing collector ring 9which in turn is secured to the centrifuge housing by means ofa clampring 10 bolted to the housing by bolts 55. In this view, it may be seenthat liquid introduced to the central chambers 13 will be caused to flowradially outward into the cavities 17 upon rotation of the rotor as thecentrifuge housing is rotated. Any fluid in excess of the volumetriccapacity of each of the respective cavities will overflow the cavity andpass through the overflow 20 into the cuvette 8 disposed radiallyoutwardly from the overflow 20. That liquid flowing through the overflowinto the cuvette is collected in the most radially outward tip of thecuvette which, by design, is disposed in register with appropriateopenings 24 in the centrifuge housing so that a light beam may be passedthrough the cuvettes for monitoring purposes.

In conducting one kind of analysis employing the present invention, arotor is initially loaded with a quantity of specimen, for example humanblood, at a station remote from the centrifugation system depicted inFIGURES. At such station (which is not depicted in the FIGURES), aquantity of blood is admitted to each of the individual chambers 13.This quantity of blood need not be measured exactly and the primaryrequirement is that the quantity admitted to each chamber be in excessof the volumetric capacity of the respective cavity of each chamber. Itthus becomes evident that the absence of a requirement of accuracy inmeasuring the quantity of blood admitted to each chamber reduces thetime required for an operator to introduce the blood specimen to eachchamber. After each chamber has been provided with its respectivequantity of blood (it is not necessary that each chamber have the samequantity, rather it is anticipated that no two chambers will have thesame quantity of blood unless by coincidence the operator happens topour identical amounts into several chambers), the rotor, while still atthe remote station, is rotated to displace the blood radially outwardinto the several cavities and eject from the rotor all quantities ofblood in excess of the respective volumetric capacities of the cavitiesat the chosen rotational speed of the rotor.

Having been rotated to eject excess specimen from the respectivecavities, the rotor is brought to rest. The blood within the respectivecavities, of course, recedes from the cavity and disperses itself withinthe respective chambers. However, it will be recognized that none of theblood can escape from the chambers and upon rotation of the rotor at asubsequent time, the blood will merely recollect within the respectivecavities.

After the rotor has been brought to rest, a displacement body isadmitted to each of the chambers 13. This displacement body may take theform of a solid sphere or other appropriate body which is capable ofdisplacing a quantity of liquid when immersed in the liquid and which isinert in the presence of the liquid to be displaced. The displacementvolume of the body must be known or capable of being calculated and inthe preferred operation, all of the displacement bodies have identicaldisplacement volumes. One desirable displacement body is a sphericalglass bead, these beads being preferred because of their inertness, andthe ease with which their displacement volume can be determined. Also,such beads are readily obtainable at a reasonable cost. V

The displacement bodies, hereinafter referred to as beads forconvenience, may be admitted to the rotor chambers while the rotor is atrest as noted above or the centrifugal forces accompanying rotorrotation may be used to assist in introducing the beads into thechambers. One embodiment of apparatus for dispensing the heads isdepicted in FIG. 5. This apparatus includes a central post having itslower end 26 centrally bored to receive a lug 27 upstanding centrallyfrom the bottom 28 of the'rotor 7. The top portion of the post 25,indicated generally by the numeral 29, is provided with a plurality ofchannels 30 serving as storage channels for a plurality of beads 31residing therein. The bottom of each respective channel 30 is open forpermitting the dispensing of'beads from each channel. The top portion 29of the post 25 is covered by a cap 32 slidably disposed over the post.The open end of the cap. depends downwardly over thetop portion 29 ofthe post to cover the several openings of the channels 30. The innerwall of the cap is cavitated at each point where the cap covers achannel opening.

A further apparatus for dispensing beads into the several chambers ofthe rotor is depicted in FIG. 6. This further apparatus comprises acentral post 40 having a lowermost portion 41 received in the hollowcentral post 22 of the rotor 7. This post 40 has an annular flange 42which rests against the top of rotor 7 thereby supporting the post 40above the rotor 7. Preferably the engagement between the rotor and postis such as will lock the postin rotational engagement with the rotor. Across-sectional view of this dispensing device is de picted in FIG. 7,the view of FIG. 7 being taken along the line 7-7 of FIG. 6. Theuppermost portion 43 of the post 40 is joined by a plurality ofpartitions 44 to an encapsulating annular sleeve 45 so as to define aplurality of bead-receiving channels 46. The annular sleeve preferablyextends vertically higher than the top portion of the post 40 to definea storage chamber 47 for a plurality of beads. The top portion 43 of thepost 40 is preferably tapered and extends upwardly into the storagecavity 47 so that the beads'are readily directed into the severalchannels 46 for dispensing into the chambers of the rotor. As desired acap 48 may be provided for closing the top of the storage chamber 47.

The cavity 34 provided in the inner wall of the cap at each such channelopening is partially closed by a wedge 35 slidably mounted in an opening37 in post 25 and spring-biased outwardly to cooperate with cavity 34 tomaintain a single sphere within the cavity at any one time as indicatedin FIG. 5. Cap 32 is biased in the upward direction by a spring 38 so asto maintain the lower rim of the cap 32 urged in a closed positionadjacent the wedge 35 thereby preventing dispensing of beads from theseveral channels 30. However, when the cap 32 is pressed downwardlyagainst the force of spring 38, the wall of cavity 34 urges the headwhich is captured in the cavity against the wedge surface of the wedge35 forcing it to slide inwardly and permit the bead to pass by thewedge. As the bead passes by the wedge 35, the spring 36 forces thewedge radially outward toward the cap 32 thereby preventing release ofmore than one bead per each downward movement of the cap 32. The beadwithin the cavity 34 which bypasses the wedge 35, enters a furthercavity 39 provided in the post 25. This further cavity 39 is of asufficiently large volume so that as the bead passes from cavity 34 intocavity 39, the bead is allowed to escape from between the cap and thepost and enter the rotor chamber directly beneath the opening.

The inner wall of the sleeve 45, at its lower rim, is provided with acavity 49 adjacent the lower portion of each of the channels 46. Thiscavity 49 may be in the form of an annular groove extending around theinner wall of the sleeve 45, but in any event, the lower wall of thecavity slopes upwardly for purposes which will appear in furtherdiscussion. The lower end of the sleeve 45 terminates above the shoulder42 by a distance sufficient to permit the passage therebetween of asingle head. The annular shoulder 42 is provided with an annular ridge50 on the upper surface of the shoulder 42.

This ridge upstands to provide an obstruction against the passageof thebead radially outward from the post 40. No obstruction is provided atthe lower end of each of the channels-46 so that at all times when therotor is at rest there will be a single bead from each channel restingon the upper surface of the shoulder 42 and radially inward from theannular ridge 50. The several beads on the shoulder may be separatedlaterally by partitions on the shoulder (not shown) or by extensions ofthe partitions 44. Upon commencement of rotation of the rotor 7, thecentrifugal forces against the beads will cause those beads residing onthe annular shoulder 42 to be forced over the ridge 5i) to fall into therespective chambers irnmediately beneath each of the channels. At thesame time the centrifugal forces acting upon that bead which is next inline for dispensing, will force such bead radially outward and intocontact with the upwardly sloping wall of the cavity 49 therebypreventing the bead from falling out of its channel and at the same timeblocking the passage of successive beads into position on the shoulder$2 for dispensing. Once the rotor has again been brought to rest, thecentrifugal forces are relieved and this next bead falls into positionfor dispensing when the rotor is again rotated.

As stated hereinbefore, when the rotor is rotated, the beads and theliquid within the respective chambers are displaced into the respectivecavities and that volume of liquid displaced by the bead in each cavityis caused to overflow the cavity and be expelled from the rotor tion tothe overflow. By this means there is dispensed from each cavity a knownquantity of liquid into each of the cuvettes.

The foregoing described apparatus and procedure for introducing aselected quantity of specimen into each of the cuvettes may be repeatedas many times as desired for purposes of successively introducingreagents or additional material to the respective cuvettes to obtain thedesired reaction. The present invention provides much freedom in theselection of the number of reagents and/or the time at which a reagentmay be introduced to the cuvette. For example, after a reaction has beencommenced with a first reagent, a further reagent may be added as may bedesired in a particular analysis.

A further feature of the present invention includes the concept ofsimultaneously introducing a plurality of liquids to a cuvette. Thisconcept is generally depicted in the apparatus of FIG. 6 which includesa plurality of rotors of the kind described hereinbefore stacked one ontop of the other within the centrifugation system housing. In accordancewith this feature of the invention, the first rotor 51 may be loadedwith a specimen, human blood for example, at a remote station asdescribed hereinbefore and an appropriate bead placed within each of thechambers of the rotor. This loaded rotor is first placed in thecentrifuge housing. A second rotor 7 is likewise loaded at a remotestation. This second rotor may contain the reagent which it is desiredbe reacted with the specimen. As desired, the second rotor may beprovided with a bead within each of its chambers atthe remote stationand before the rotor is introduced into the centrifugation system or,al-

tematively, the beads may be added to the chambers of this second rotor7 by any of the means herebefore described. With these two rotors inposition in the centrifugation system, the apparatus is rotated.Thereupon, the liquid within each of the several cavities is displacedby the beads within the cavities and is caused to overflow the cavities,be expelled from the rotor, and received in the corresponding cuvettes.It is noted that the liquids from the two rotors are dischargedsimultaneously into the respective cuvettes where they become mixed andreact. The capability provided by the present invention tosimultaneously introduce measured quantities of two or more liquids intothe cuvette enhances the usefulness of the centrifugation system conceptin that it is possible by means of the present invention to observe theprogress of reactions which require the simultaneous combination of twoor more liquids if the reaction is to occur.

The present method and apparatus make possible the preparation ofspecimens and reagents at stations remote from the centrifugationapparatus. This capability not only frees the centrifugation apparatusfor use in conducting analyses as distinguished from its being tied upduring pipetting procedures or the like but it also makes possible thepreparation of specimens and reagents with a savings of time. The remotestation referred to herein may comprise a centrifuge of uncomplicatedconstruction such as a rotated holder for the rotor with an overflowcatch basin as will be apparent to one skilled in the art. The cavitiesprovided in the rotor disclosed herein permit rapid and accurate loadingof the rotor chambers without tedious attention to the introduction ofaccurately measured quantities of liquid to each chamber. The presentinvention allows the operator or technician to pour relatively grossquantities of liquid into each chamber and then merely spin the rotor toexpel any liquid in excess of the volumetric capacity of the cavityassociated with each chamber. Rotors as disclosed herein may bemanufactured readily and inexpensively by known means and usinginexpensive materials such as by injection molding of plastic. Thusrotors having differently-sized cavities may be economically provided asdesired for various analyses and in most instances will be disposableitems.

In addition, it is possible with the present apparatus and method toprepare a rotor loaded with reagent and a displacing bead within each ofits chambers and store this rotor under appropriate conditions, forexample by freezing, until the reagent is needed for use in conductingan analysis. The same capability is provided concerning the preparationof specimens. For example, blood specimens may be taken from a patientand immediately loaded into'the rotor along with a bead in.

each of the chambers of the rotor and then frozen for subsequentanalysis.

While preferred embodiments have been shown and described, it will beunderstood that there is no intent to limit the disclosure, but rather,it is intended to cover all modifications and alternate constructionsfalling within the spirit and scope of the invention as defined in theappended claims.

What is claimed is:

l. A rotor system comprising a rotor having a rotational axis,

a plurality of radial cavities in said rotor disposed in generallyconcentric array about said rotational axis of said rotor for receivingand retaining respective quantities of liquid when said rotor isrotated,

overflow means associated with each of said cavities and adapted todischarge from said cavity any liquid in excess of the volumetriccapacity of said cavity at the instant rotational speed of said rotor,and

displacement means disposed in each of said cavities,

said displacement means in each cavity displacing a quantity of liquidwithin each of said cavities, said quantity of displaced liquid in eachcavity being essentially equal to the liquid displacement volume of thedisplacement means in respective cavities, whereby said displacedquantities of liquid are expelled from respective cavities through theirrespective overflows upon rotation of said rotor with said displacementmeans in said cavities.

2. The rotor system of claim 1 and including dispensing means disposedin superposition to said rotor and including a plurality of displacementbodies for simultaneous admission to said cavities in said rotor.

3. The rotor system of claim 1 wherein said displacement means comprisesa solid body of generally spherical geometry.

4. The rotor system of claim 1 wherein said solid body comprises a glassbead.

5. A dispenser device for simultaneously dispensing a plurality ofdisplacement bodies into separate compartments of a rotor comprisingmounting means releasably mounting said dispenser device in rotationalengagement with said rotor in the approximate center of said rotor andabove said compartments,

a plurality of channel means in said device, respective ones of saidchannels being in alignment with and disposed above respective-ones ofsaid compartments when said dispenser device is mounted on said rotor,each of said channels being open at its lower end,

at least one generally spherical displacement body disposed in each ofsaid channel means,

detentionmeans retaining said displacement bodies within said channelsand adapted to selectively and simultaneously release one body from eachchannel whereby said bodies are free to fall into said compartments.

6. The dispenser device of claim wherein said detention means comprisesan annularmember having an inner wall disposed adjacent to said loweropenings of said channels and spaced apart therefrom by a distancegreater than the diameter of a displacement body but less than twice thediameter of a displacement body, a cavity in said inner wall of saidannular member adjacent each of said lower openings of said channels,said cavity being of a depth such that a displacement body residing insaid cavity projects into its respective channel a distance sufficientto preclude the passing of another displacement body therepast, saidcavity including an upwardly inclined wall portion defining its lowerdimension whereby when said dispenser is rotated the centrifugal forcesaccompanying such rotation forces a displacement body from each channelinto said cavity to preclude the release of displacement bodies fromsaid channels but when said dispenser is not rotating said bodies arereleased for movement out of said channels, retainer means disposedbeneath said channels and spaced therefrom by a distance sufficient topermit the passage of not more than one displacement body therebetween,ridge means disposed on the upper side of said retainer means anddefining a barrier against radial movement of displacement bodies exceptwhen said dispenser means is rotated at a rotational speed sufficient tocause said bodies to overcome said barrier.

7. A method for manipulating liquid matter employ ing a rotor systemcomprising the steps of:

admitting a quantity of said liquid matter to each of a plurality ofholding chambers in said rotor, each of said chambers having at leastone radially outward cavity portion adapted to receive and retain aquantity of said liquid when said centrifuge is rotated at a speedsufficient to displace said liquid radially outwardly, each of saidcavities having an overflow including a weir,

rotating said rotor with said liquid in said chambers whereby any liquidin excess of the capacity of said cavity portions of said chambers atthe instant rotational speed of said rotor overflows said weir and isexpelled from each cavity through its overflow,

admitting tdeach of said chambers a body having a knowndis'placementvolume whereby upon sub sequent rotation of said rotor there isdisplaced in each cavity a quantity of liquid substantially equal t di eetvl e f 'dbod ands'd disgl ce li guiii in a i: cgwit y overi lows t lierespective weir of each cavity and is expelled from said rotor, andcollecting said overflowing displaced liquid in collecting meansdisposed in juxtaposition to said overflows. I 8. A method formanipulating a liquid employing a rotor system including a plurality ofliquid receptacles the improvement comprising the steps of:

providing a multi-chamber rotor having a plurality of radially disposedcavities, each of said cavities having an overflow through which anyquantity of liquid in said cavity that is in excess of the volumetriccapacity of said cavity is discharged upon rotation of said rotor,introducing a gross quantity of liquid to each of said rotor chambers,rotating said rotor to force said liquid into said cavities and causethe discharge from the cavities of any liquid which is in excess oftheir respective volumetric capacities, admitting a displacement body ofknown liquid displacement volume to each of said cavities, introducingsaid rotor into means for rotating said rotor with each of said cavityoverflow means being disposed in juxtaposition to a corresponding liquidreceptacle, corresponding liquid rotating said rotor whereby saiddisplacement bodies displace liquid in each cavity, said displacedliquid in each cavity being discharged from said cavity through itsrespective overflow means and collected in said respective receptacles.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, 683,973' Dated August 15, 1972 Inventor(s) Donald W. Hatcher, SI.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

Signed and sealed this 13th day of February 1973.

(SEAL) Attest:

ROBERT GOTTSCHALK EDWARD M.FLETCHER,JR.

Commissioner of Patents Attesting Officer FORM PO-105O (10-69) UscoMM-DCsuave-Pd W U.S. GOVERNMENT PRINTING OFFICE 1 l9, 0

1. A rotor system comprising a rotor having a rotational axis, aplurality of radial cavities in said rotor disposed in generallyconcentric array about said rotational axis of said rotor for receivingand retaining respective quantities of liquid when said rotor isrotated, overflow means associated with each of said cavities andadapted to discharge from said cavity any liquid in excess of thevolumetric capacity of said cavity at the instant rotational speed ofsaid rotor, and displacement means disposed in each of said cavities,said displacement means in each cavity displacing a quantity of liquidwithin each of said cavities, said quantity of displaced liquid in eachcavity being essentially equal to the liquid displacement volume of thedisplacement means in respective cavities, whereby said displacedquantities of liquid are expelled from respective cavities through theirrespective overflows upon rotation of said rotor with said displacementmeans in said cavities.
 2. The rotor system of claIm 1 and includingdispensing means disposed in superposition to said rotor and including aplurality of displacement bodies for simultaneous admission to saidcavities in said rotor.
 3. The rotor system of claim 1 wherein saiddisplacement means comprises a solid body of generally sphericalgeometry.
 4. The rotor system of claim 1 wherein said solid bodycomprises a glass bead.
 5. A dispenser device for simultaneouslydispensing a plurality of displacement bodies into separate compartmentsof a rotor comprising mounting means releasably mounting said dispenserdevice in rotational engagement with said rotor in the approximatecenter of said rotor and above said compartments, a plurality of channelmeans in said device, respective ones of said channels being inalignment with and disposed above respective ones of said compartmentswhen said dispenser device is mounted on said rotor, each of saidchannels being open at its lower end, at least one generally sphericaldisplacement body disposed in each of said channel means, detentionmeans retaining said displacement bodies within said channels andadapted to selectively and simultaneously release one body from eachchannel whereby said bodies are free to fall into said compartments. 6.The dispenser device of claim 5 wherein said detention means comprisesan annular member having an inner wall disposed adjacent to said loweropenings of said channels and spaced apart therefrom by a distancegreater than the diameter of a displacement body but less than twice thediameter of a displacement body, a cavity in said inner wall of saidannular member adjacent each of said lower openings of said channels,said cavity being of a depth such that a displacement body residing insaid cavity projects into its respective channel a distance sufficientto preclude the passing of another displacement body therepast, saidcavity including an upwardly inclined wall portion defining its lowerdimension whereby when said dispenser is rotated the centrifugal forcesaccompanying such rotation forces a displacement body from each channelinto said cavity to preclude the release of displacement bodies fromsaid channels but when said dispenser is not rotating said bodies arereleased for movement out of said channels, retainer means disposedbeneath said channels and spaced therefrom by a distance sufficient topermit the passage of not more than one displacement body therebetween,ridge means disposed on the upper side of said retainer means anddefining a barrier against radial movement of displacement bodies exceptwhen said dispenser means is rotated at a rotational speed sufficient tocause said bodies to overcome said barrier.
 7. A method for manipulatingliquid matter employing a rotor system comprising the steps of:admitting a quantity of said liquid matter to each of a plurality ofholding chambers in said rotor, each of said chambers having at leastone radially outward cavity portion adapted to receive and retain aquantity of said liquid when said centrifuge is rotated at a speedsufficient to displace said liquid radially outwardly, each of saidcavities having an overflow including a weir, rotating said rotor withsaid liquid in said chambers whereby any liquid in excess of thecapacity of said cavity portions of said chambers at the instantrotational speed of said rotor overflows said weir and is expelled fromeach cavity through its overflow, admitting to each of said chambers abody having a known displacement volume whereby upon subsequent rotationof said rotor there is displaced in each cavity a quantity of liquidsubstantially equal to the displacement volume of said body and saiddisplaced liquid in each cavity overflows the respective weir of eachcavity and is expelled from said rotor, and collecting said overflowingdisplaced liquid in collecting means disposed in juxtaposition to saidoverflows.
 8. A method for manipulating a liquid employing a rotorsystem Including a plurality of liquid receptacles the improvementcomprising the steps of: providing a multi-chamber rotor having aplurality of radially disposed cavities, each of said cavities having anoverflow through which any quantity of liquid in said cavity that is inexcess of the volumetric capacity of said cavity is discharged uponrotation of said rotor, introducing a gross quantity of liquid to eachof said rotor chambers, rotating said rotor to force said liquid intosaid cavities and cause the discharge from the cavities of any liquidwhich is in excess of their respective volumetric capacities, admittinga displacement body of known liquid displacement volume to each of saidcavities, introducing said rotor into means for rotating said rotor witheach of said cavity overflow means being disposed in juxtaposition to acorresponding liquid receptacle, corresponding liquid rotating saidrotor whereby said displacement bodies displace liquid in each cavity,said displaced liquid in each cavity being discharged from said cavitythrough its respective overflow means and collected in said respectivereceptacles.